The overall goal of this project is to develop a novel rehabilitation tool for the treatment of patients with balance disorders using virtual reality (VP.). Based on their extensive experience using balance rehabilitation therapy, which is a non-surgical, non- pharmaceutical treatment for patients with balance disorders, the investigators plan to develop VP protocols to improve this treatment modality. Thus, they propose to develop VR techniques appropriate for patients with balance disorders. The research team consists of persons with expertise in bioengineering. physical therapy, neurology, clinical psychology, and computer science. By combining their efforts, they plan to develop a visual display booth using PC-based technology that will allow them to gain insights into how VR can be used effectively as a new rehabilitation tool by therapists with expertise in balance disorders. The essential components of the visual display booth are already in place at the University of Pittsburgh Medical Virtual Reality Center. Using this existing facility as a starting point for our research, The investigators plan to 1) develop appropriate software and hardware for the application of VR to balance rehabilitation therapy, 2) perform pre-clinical studies in normal subjects and selected patients across the age spectrum to develop ideas regarding tolerance, treatment methodologies, appropriate durations of exposure, and potential response measures, and 3) develop specific VR protocols for balance therapy and perform pilot clinical studies. For Experiment 1, the visual scenes will be primitive and will include selected charactenstics known to be both challenging to patients with balance disorders and, they believe, useful in the rehabilitation process. These primitive scenes will be chosen to provide insight as to how to design a virtual grocery store, which will serve as the basis for Experiment 2. The VP facility will enable the therapist to provide graded amounts of visual complexity and visual motion in a physically safe and psychologically secure setting while patients perform typical eye and head movements essential for activities of daily living.